The vehicle was on a divided highway with Autopilot engaged when a tractor trailer drove across the highway perpendicular to the Model S. Neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied. The high ride height of the trailer combined with its positioning across the road and the extremely rare circumstances of the impact caused the Model S to pass under the trailer, with the bottom of the trailer impacting the windshield of the Model S.

Contrary to certain media reports, it is important to remember that using Autopilot mode does not make the Tesla a self-driving car. Not only is the Autopilot software itself still in beta testing (i.e. not ready for widespread public use), the driver is required to ensure their hands remain on the steering wheel at all times, and to be prepared to resume manual driving at any moment. Enabling Autopilot does not mean the driver can take their eyes off the road or lose awareness of their surrounding environment.

The New York Times article linked above later quotes Karl Brauer, an analyst with the American automotive research firm Kelly Blue Book:

This is a bit of a wake-up call,” Mr. Brauer said. “People who were maybe too aggressive in taking the position that we’re almost there, this technology is going to be in the market very soon, maybe need to reassess that.

Karl Brauer's statement needs to be placed into context. The vastmajority of car accidents are caused at least in part by human error. So there is no doubt that when used as intended (as an assistive feature that warns the driver of any potential hazards, but over which the driver maintains full control), Tesla's Autopilot can only improve road safety. Citing a single misuse of Autopilot as a justification to call for all autonomous driving technologies to be re-assessed in terms of their safety and viability on the road is, frankly, misleading.

Nevertheless, it is clear that true driverless cars in the near future will be a significant enough departure from current vehicles that they will require their own set of regulations and governing laws. Perhaps a safety and regulations agency, in the vein of the Global NCAP, but for driverless cars, could be created to consolidate and ensure uniform regulations for autonomous vehicles?

As tragic as it may be, it is also plain that the introduction of such technology will have teething issues, as society adapts to driverless vehicles, and that the consequences of these teething issues could involve fatal accidents. What is important, however, is for regulators and the media to not lose sight of the overall view that autonomous technologies are not detrimental to, but instead enhance, road and driver safety and are beneficial to society.

Thus, any future regulations relating to driverless vehicles must not be knee-jerk, impulsive reactions to accidents such as the imposition of bans or other widespread restrictions, but should instead empower the development of this new technology.